The present invention relates generally to silica wires having sub-micrometer or nanometer-sized diameters, and methods for forming such wires, and more particularly, to fabrication methods that provide nano-sized silica wires having enhanced uniformity and surface smoothness.
Miniature silica waveguides with diameters or widths larger than the wavelength of transmitted light are widely utilized in optical communications, sensors, and other applications. Silica wires with diameters more than one micrometer, which allow multimode waveguiding of visible and infrared radiation, can be made by drawing high-purity glass fibers from a laser-heated melt. Although photonic applications can benefit from incorporation of silica submicrometer- or nanometer-diameter wires (SMNW), the fabrication of such silica wires presents a number of challenging problems. In particular, both theoretical and experimental results indicate that the laser power required for drawing silica SMNWs with a uniform diameter from a laser-heated melt is impractically large. Further, it is difficult to draw SMNWs having uniform diameters from a flame-heated melt because turbulence and convention render controlling the temperature gradient in the drawing region problematical. Moreover, silica nanowires obtained recently by employing other methods exhibit large diameter fluctuations and sidewall roughness that render these wires unsuitable for low-loss optical waveguiding.
Hence, there is a need for silica fibers having submicrometer- or nanometer diameters that exhibit enhanced diameter uniformity and surface smoothness.
There is also a need for methods that allow fabrication of such silica fibers.